There's I-enhance menu, and i adjust the Sharpness to "+2", is it sharper for the image?

This only applies to JPEG shooting, and the sharpness is software-enhanced.
Try to shoot with the camera on a tripod, and with a 2-seconds-delay-timer.
If that makes no sharp pics, it could be back/front focus issue.

As for 'good' pictures, I am still searching, so can't give you any advice but keep on shooting :-D.

-- hide signature --

"When I get a little money I buy books; and if any is left I buy food and clothes" - Erasmus.